1998 sye kit in a 1991 - wouldnt fit?

blondejoncherokee · Sep 8, 2015

I gave a SYE kit from my 1998 XJ to a buddy. He tried to install it in his 1991 XJ and said it would not shift.
Both are np231s. My rig was a auto, he has a manual. I thought all np231 SYE would fit any year 231 from 1984-2001?

He said the rear output shaft had different splines going into the front of the case at the planetaries . Every SYE I have installed has just worked.

He lives a couple hours away and I am trying to get better details, but has anyone had this issue before ? I think maybe he did something wrong.

Digger87xj · Sep 8, 2015

the only answer is he was putting it together wrong.

Maybe?: The early t-cases you have to press out and leave out a set of needle bearings from the chain drive gear. it won't fit over the output shaft with the bearings installed. Later model t-cases didn't have the bearings.

mtbxj87 · Sep 8, 2015

he probably needs to cut the shift fork shaft down. I had to cut about 5/8'' off mine

Digger87xj · Sep 8, 2015

mtbxj87 said:
he probably needs to cut the shift fork shaft down. I had to cut about 5/8'' off mine

yep, that too..!!!

blondejoncherokee · Sep 8, 2015

mtbxj87 said:
he probably needs to cut the shift fork shaft down. I had to cut about 5/8'' off mine

ah ok. the fork itself ? which part of the fork has to be cut exactly ? I have never heard this before.

blondejoncherokee · Sep 8, 2015

Digger87xj said:
the only answer is he was putting it together wrong.

Maybe?: The early t-cases you have to press out and leave out a set of needle bearings from the chain drive gear. it won't fit over the output shaft with the bearings installed. Later model t-cases didn't have the bearings.

interesting. Ill ask him about this.

Digger87xj · Sep 8, 2015

blondejoncherokee said:
ah ok. the fork itself ? which part of the fork has to be cut exactly ? I have never heard this before.

The fork rail shaft...not the fork.

blondejoncherokee · Sep 8, 2015

Digger87xj said:
The fork rail shaft...not the fork.

Ah ok. Why is that ?

Digger87xj · Sep 8, 2015

the end of the shaft where it pokes through the back case is too long (on early models) for the sye conversion. its all laid out in the destructions...

blondejoncherokee · Sep 9, 2015

Digger87xj said:
the end of the shaft where it pokes through the back case is too long (on early models) for the sye conversion. its all laid out in the destructions...

yeah there are no instructions. Just a case I ripped off my rig to install my atlas. the case had a ruined shift fork.

I guess I need to find some instructions. Ive watched a bunch of right ups and they haven't mentioned that part.

Digger87xj · Sep 9, 2015

Advance adapters has PDF instructions on their site

blondejoncherokee · Sep 9, 2015

this and the video on AA site helped.

http://www.4wdmechanix.com/NP231-and-NV231-Jeep-Wrangler-Transfer-Case-Rebuild-Part-2.html

I found this
http://www.naxja.org/forum/showthread.php?t=74749

another quote from another thread:
I just used a cutoff wheel for the one that I had to cut down.

Here are the directions from JB Conversions instructions.

Step #11 reads:

11) Verify the length of your mode fork shift rod as shown (Fig.11). If your shift rod measures 10.2", it will need to be cut down to a length of 9.380". This is typical to 1988 and 1989 model YJ's.

That's 0.82 inches, or just about 13/16 of an inch. I would cut it down a bit on the "big" side, and then use the cutoff wheel or bench grinder to get it more exact. When it's all said & done, I would rather be a tad too short, than to have it too long & experience a clearance issue.

a pirate thread with a guy having issues:
http://www.pirate4x4.com/forum/jeep-non-hardcore/1414514-need-emergency-231-sye-help.html

blondejoncherokee · Sep 9, 2015

Thanks for all the help. I would have never known to search for the range shifter shaft . I told him about that and he had already put the old setup back on, so Ill talk him through it.

ehall · Sep 9, 2015

Is it the AA or the JB? They are similar but some minor difference. The AA has a large lip at the end of the output housing, while the JB has a small lip that is similar to the stock housing. Also the older AA has a fixed hole for the rail, while the JB has a threaded hole with a plug for the rail (edit--I think the new AA housings also have the threaded hole). This is the AA and the JB, in order

1998 sye kit in a 1991 - wouldnt fit?

blondejoncherokee

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